LAN9500 Datasheet, PDF (97/213 Pages) SMSC Corporation – USB 2.0 to 10/100 Ethernet Controller Promiscuous mode

LAN950x
• MAC Address High Register (ADDRH) and MAC Address Low Register (ADDRL)
• Hardware Configuration Register (HW_CFG)
• LED General Purpose IO Configuration Register (LED_GPIO_CFG)
• General Purpose IO Wake Enable and Polarity Register (GPIO_WAKE)
5.9 Device Clocking
The device requires a fixed-frequency 25MHz clock source. This is typically provided by attaching a 25MHz crystal to
the XI and XO pins. The clock can optionally be provided by driving the XI input pin with a single-ended 25MHz clock
source. If a single-ended source is selected, the clock input must run continuously for normal device operation.
Internally, the device generates its required clocks with a phase-locked loop (PLL). It reduces its power consumption in
several of its operating states by disabling its internal PLL and derivative clocks. The 25MHz clock remains operational
in all states where power is applied.
5.10 Device Power Sources
The device may be soft powered by the USB bus or self powered via external power supplies. The following external
3.3V power supplies are required when power is not being furnished by the USB bus:
• VDD33IO, VDD33A
Note: The device also uses power supplied by an internal regulator and connection does not vary. Since the reg-
ulated supply is derived from VDD33IO, there is no need to discuss it separately.
5.11 Power States
The following power states are featured.
• UNPOWERED
• NORMAL (Unconfigured and Configured)
• Suspend (SUSPEND0, SUSPEND1, SUSPEND2, and SUSPEND3)
All four SUSPEND states are supported by LAN9500A/LAN9500Ai. SUSPEND3 is not supported by
LAN9500/LAN9500i.
Figure 5-29 illustrates the power states and allowed state transitions.
FIGURE 5-29:
POWER STATES
!V B U S _ D E T
(Any state)
UNPOWERED
VBUS_DET
Asserted
(PO R || nRESET ||
USB Reset || SRST)
&& VBUS_DET
NORMAL
(Unconfigured )
USB Resum e ||
W OL ||
G P IO
USB Suspend
D e c on fig u re d
C on fig ure d
NORMAL
(C o n fig u re d )
USB Suspend
USB Resum e ||
G P IO
USB Resum e ||
Energy Detect ||
G P IO
USB Suspend
USB Suspend
USB Resume ||
Fram e Received ||
G P IO
USB Resum e ||
G P IO
USB Suspend
SUSPEND0
SUSPEND1
SUSPEND3
SUSPEND2
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DS00001875A-page 97